21. 故善戰者求之於埶不責於人故能擇人而任埶
22. 任埶者其戰人也如轉木石木石之性安則靜危則動方則止圓則行
23. 故善戰人之勢如轉圓石於千仞之山者埶也

21. The clever combatant looks to the effect of combined energy, and does not require too much from individuals. Hence his ability to pick out the right men and utilize combined energy.

22. When he utilizes combined energy, his fighting men become as it were like unto rolling logs or stones. For it is the nature of a log or stone to remain motionless on level ground, and to move when on a slope; if four-cornered, to come to a standstill, but if round-shaped, to go rolling down.

23. Thus the energy developed by good fighting men is as the momentum of a round stone rolled down a mountain thousands of feet in height. So much on the subject of energy.